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Homebrew Camera Mod Mimics LANDSAT Satellite

Posted by timothy on from the for-the-neighborhood-watch-with-dea-ambitions dept.

An anonymous reader writes "These folks at Public Lab have published instructions to hack a conventional camera to do photosynthesis photography, just like NASA's LANDSAT satellite. What better way to introduce your kids to space technologies and learn more about the environment? Measure the health of your garden, all with a simple filter switch and some post-processing. It's thoroughly documented at http://publiclab.org/wiki/near-infrared-camera, and you can do it to a variety of cameras." (And here's a link to the related — and fully funded — kickstarter project.)

7 of 21 comments (clear)

  1. Infrared filter? by Anonymous Coward · · Score: 2, Insightful

    DNRTFA, but can I assume that we're talking about removing the infrared filter that is integrated into most cameras made in the last 15 years, and the hack for which has been available on the net for just about as long? It was all the rage when people found out that you could take nudie pics at the beach with this trick.

    1. Re:Infrared filter? by Anonymous Coward · · Score: 4, Informative

      The change is to *replace* the IR filter with a notch filter that just removes the visible red, while leaving the near IR and green/blue light. The combination is interesting for detecting plants.

          http://publiclab.org/notes/cfastie/04-20-2013/superblue

    2. Re:Infrared filter? by sjames · · Score: 2

      That's step 1. Step 2 was to filter out red light instead (making the red channel of the photo be an IR channel) by finding an off the shelf filter that happens to do the needed thing. Step 3 is post-processing to make that into useful information.

      Step 2 took a bit of research since most filters that don't cost more than the camera don't say anything about passing near IR or not. They just had to try a few and see which ones just happened to.

      Then, of course there's writing the code to do the post processing.

    3. Re:Infrared filter? by sjames · · Score: 2

      If it could be ANY 20 lines of code, it would be trivial. Alas, it needs to be the correct 20 lines or the results are worthless. Which 20 lines are useful is a matter of understanding, educated guesses and trial and error.

    4. Re:Infrared filter? by Lumpy · · Score: 2

      If you took a photo of a person in a perfect camoflauge suit, they will stand out like a beacon with this camera mod.

      It will work great for detecting non living organic things in camo easily.

      --
      Do not look at laser with remaining good eye.
    5. Re:Infrared filter? by jythie · · Score: 2

      I would put it at worse, but only because this is a cheaper way of doing it.

      Usually what you have to do is either get a broad spectrum conversion then get a special cut filter or have the cut filter put in the camera.... or have a tri-shot monochrom setup so you can be extra sure which wavelengths are getting into which channel.

      What they are doing here is similar to the old trick of using exposed film as an IR filter or shards of blacklight bulb as a UV filter, they found a cheap substitute for the high grade filters one would use for professional or scientific work.

      That being said I am in favor of projects that let people play with exotic photography on a budget.

  2. Why not use iPhone 4/4S Facetime Camera by KJSwartz · · Score: 3, Interesting

    Similar effect - the main camera is filtered, but I've learned that the 2nd camera is not..
    Resolution may not be good, but should be adequate for proof-of-concept.